Summers and Leek (1994) demonstrated that listeners with moderate hearing
loss have a reduced ability to identify spectral peaks in broadband stimuli
coincident with increased auditory filter bandwidths, but that abilities were
presumed sufficient for vowel identification. The current study investigated
spectral ripple detection and ripple frequency discrimination with listeners
having moderate and severe losses. Stimuli were flat spectrum pure-tone
complexes log-spaced over 2-oct bands (1000--4000 Hz and 500--2000 Hz). In one
experiment the different signal's spectrum was multiplied by sinusoidal
log-spaced ripples. Ripple frequency was held constant while ripple amplitude
adapted. In the second experiment, all signals contained constant-amplitude
ripples with ripple frequency adapting. Preliminary results for moderate loss
listeners indicate ripple detection thresholds for both 2-oct band stimuli are
similar to those previously reported. Comparatively, listeners with flat severe
losses have markedly poorer ability to detect spectral peaks, and performed
significantly poorer for detecting ripples in the higher-frequency stimuli than
in the lower-frequency stimuli. Results suggest that vowel distinctions based on
formant discrimination may be difficult for these listeners. Also, deficient
consonant identification may be associated with reduced ripple detection
ability; the severely hard-of-hearing listener with the largest ripple threshold
also had the poorest word identification. [Work supported by NIDCD Grant No.
K0800124.]